The present invention relates to an image generating method and an MRI (Magnetic Resonance Imaging) apparatus, and more specifically to an image generating method and an MRI apparatus capable of generating an MR image excellent in image quality, based on respective data obtained by n (≧2) coils.
One MR image has heretofore been generated by a sum of square method based on respective data obtained by coils of a phased array coil. However, a satisfactory image cannot be obtained due to variations in sensitivity of each coil. Therefore, there has been proposed a method of acquiring data by a body coil having uniform sensitivity to thereby create a reference image, and correcting the sensitivity of each coil using the reference image (refer to, for example, the following patent document 1).
There has been also proposed a method of generating images from respective data obtained by n coils and sensitivity maps of the respective coils (see, for example, the following non-patent document 1).
[Patent Document 1] U.S. Pat. No. 4,812,753
[Non-Patent Document 1] Pruessmann K P, et al. Magn Reson Med 1999; 952-962
The conventional method of correcting the sensitivity, based on the reference image generated from the data obtained using the body coil is accompanied by the problem that the acquisition of data by the body coil is needed in addition to the acquisition of data by the phased array coil. Also a problem arises in that when a patient moves during the periods of the acquisition of the data by the phased array coil and the acquisition of the data by the body coil, an artifact is generated.
Further, the known method of generating the images from the respective data obtained by the n coils and the sensitivity maps of the respective coils is accompanied by the problem that although the sensitivity maps of the respective coils are required, the acquisition of data by a body coil is required in addition to the acquisition of data by a phased array coil to create the sensitivity maps. When a patient moves during the periods of the acquisition of the data by the phased array coil and the acquisition of the data by the body coil, an artifact occurs.